The mounting of a cutting die board or cutting die onto the rotary cylinder of a cutting machine has frequently utilized a plurality of threaded fasteners such as screws which must be manually manipulated in order to provide secure connection of the die board to the cylinder, particularly due to centrifugal forces which are generated during operation of the machine and which tend to effect separation of the board from the support cylinder. In an attempt to expedite the mounting or interchanging of the die cutting boards, attempts have been made to utilize securing devices involving magnetic systems or vacuum forces, but the disadvantage of such systems is their inability to provide a positive and secure mechanical connection between the support cylinder and the die cutting board. Quick release securing devices employing mechanical springs have also been developed, but such devices typically require springs which must have the capability of generating the requisite forces necessary to hold the die board in position in opposition to the rotational-generated centrifugal forces, and high pressure cylinders for releasing the board. These overall devices have involved undesired mechanical complexity.
It is an object of this invention to provide an improved and mechanically and operationally simplified securing device for permitting rapid fixing or attaching of the cutting die board onto the machine support, such as the rotary cylinder, and which is capable of providing a secure mechanical connection of the board to the support during the normal rotational operation of the machine.
With the improved securing arrangement of the present invention, according to one embodiment thereof, a securing bolt which engages the cutting board is coupled to a double-acting fluid pressure cylinder which is mounted on the support. The fluid pressure cylinder is selectively supplied with high pressure against one side thereof which draws the bolt inwardly into securing engagement with the board, or when mounting or demounting of the board is desired draws the bolt inwardly so that the head thereof is substantially flush with the support. As part of the mounting or demounting process, however, the high pressure is exhausted from the cylinder, and low pressure is applied to the other side of the cylinder to cause the bolt head to move outwardly through an access opening formed in the mounting board. The force generated by this low pressure cylinder, however, is such that if the bolt head does not align with an access opening in the board, then the force exerted by the bolt against the board is not sufficient to effect separation or movement thereof.
According to an alternate embodiment of the present invention, the improved securing arrangement again has a clamping bolt for engaging the cutting board, which securing bolt is coupled to the piston rod of a double-acting fluid pressure cylinder through a slip coupling which permits relative longitudinal movement when the longitudinal force transmitted therethrough exceeds a small controlled magnitude. A pressure fluid can be supplied to opposite sides of the piston for controlling extension and retraction of the bolt. However, if the clamping bolt during extension does not align with a hole in the die cutting plate, then the force applied thereto by the die cutting plate causes the slip coupling to release and allows the piston rod to extend even though the clamping bolt does not, thereby preventing excessive separation force from being applied to the die cutting plate.
Other objects of the invention will be apparent upon reading the following specification and inspecting the accompanying drawings.
Certain terminology will be used in the following description for convenience in reference only, and will not be limiting. For example, the words “upwardly”, “downwardly”, “rightwardly” and “leftwardly” will refer to directions in the drawings to which reference is made. The words “extend” and “retract” will refer to movement directions associated with the clamping bolt relative to the activating device which controls the bolt movement. The words “inwardly” and “outwardly” will refer to directions toward and away from, respectively, the geometric center of the device and designated parts thereof. Said terminology will include the words specifically mentioned, derivatives thereof, and words of similar import.